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Commit 3e5903eb9cff ("vsprintf: Prevent crash when dereferencing invalid
pointers") prevents most crash except for %pD.
There is an additional pointer dereferencing before dentry_name.
At least, vma->file can be NULL and be passed to printk %pD in
print_bad_pte, which can cause crash.
This patch fixes it with introducing a new file_dentry_name.
Link: http://lkml.kernel.org/r/[email protected]
Fixes: 3e5903eb9cff ("vsprintf: Prevent crash when dereferencing invalid pointers")
To: Geert Uytterhoeven <[email protected]>
To: Thomas Gleixner <[email protected]>
To: Andy Shevchenko <[email protected]>
To: [email protected]
Cc: Kees Cook <[email protected]>
Cc: "Steven Rostedt (VMware)" <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: "Tobin C. Harding" <[email protected]>
Signed-off-by: Jia He <[email protected]>
Reviewed-by: Andy Shevchenko <[email protected]>
Reviewed-by: Sergey Senozhatsky <[email protected]>
Signed-off-by: Petr Mladek <[email protected]>
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git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk
Pull printk updates from Petr Mladek:
- distinguish different legacy clocks again
- small clean up
* tag 'printk-for-5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk:
lib/vsprintf: Reinstate printing of legacy clock IDs
vsprintf: fix data type of variable in string_nocheck()
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When using the legacy clock framework, clock pointers are no longer
printed as IDs, as the !CONFIG_COMMON_CLK case was accidentally
considered an error case.
Fix this by reverting to the old behavior, which allows to distinguish
clocks by ID, as the legacy clock framework does not store names with
clocks.
Fixes: 0b74d4d763fd4ee9 ("vsprintf: Consolidate handling of unknown pointer specifiers")
Link: http://lkml.kernel.org/r/[email protected]
Cc: Sergey Senozhatsky <[email protected]>
Cc: Andy Shevchenko <[email protected]>
Cc: [email protected]
Signed-off-by: Geert Uytterhoeven <[email protected]>
Signed-off-by: Petr Mladek <[email protected]>
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This patch fixes data type of precision with int.
The precision is declared as signed int in struct printf_spec.
Link: http://lkml.kernel.org/r/[email protected]
To: <[email protected]>
To: <[email protected]>
To: <[email protected]>
To: <[email protected]>
Signed-off-by: Youngmin Nam <[email protected]>
Reviewed-by: Sergey Senozhatsky <[email protected]>
Signed-off-by: Petr Mladek <[email protected]>
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Add SPDX license identifiers to all files which:
- Have no license information of any form
- Have EXPORT_.*_SYMBOL_GPL inside which was used in the
initial scan/conversion to ignore the file
These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:
GPL-2.0-only
Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
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The commit 3e5903eb9cff70730 ("vsprintf: Prevent crash when dereferencing
invalid pointers") broke boot on several architectures. The common
pattern is that probe_kernel_read() is not working during early
boot because userspace access framework is not ready.
It is a generic problem. We have to avoid any complex external
functions in vsprintf() code, especially in the common path.
They might break printk() easily and are hard to debug.
Replace probe_kernel_read() with some simple checks for obvious
problems.
Details:
1. Report on Power:
Kernel crashes very early during boot with with CONFIG_PPC_KUAP and
CONFIG_JUMP_LABEL_FEATURE_CHECK_DEBUG
The problem is the combination of some new code called via printk(),
check_pointer() which calls probe_kernel_read(). That then calls
allow_user_access() (PPC_KUAP) and that uses mmu_has_feature() too early
(before we've patched features). With the JUMP_LABEL debug enabled that
causes us to call printk() & dump_stack() and we end up recursing and
overflowing the stack.
Because it happens so early you don't get any output, just an apparently
dead system.
The stack trace (which you don't see) is something like:
...
dump_stack+0xdc
probe_kernel_read+0x1a4
check_pointer+0x58
string+0x3c
vsnprintf+0x1bc
vscnprintf+0x20
printk_safe_log_store+0x7c
printk+0x40
dump_stack_print_info+0xbc
dump_stack+0x8
probe_kernel_read+0x1a4
probe_kernel_read+0x19c
check_pointer+0x58
string+0x3c
vsnprintf+0x1bc
vscnprintf+0x20
vprintk_store+0x6c
vprintk_emit+0xec
vprintk_func+0xd4
printk+0x40
cpufeatures_process_feature+0xc8
scan_cpufeatures_subnodes+0x380
of_scan_flat_dt_subnodes+0xb4
dt_cpu_ftrs_scan_callback+0x158
of_scan_flat_dt+0xf0
dt_cpu_ftrs_scan+0x3c
early_init_devtree+0x360
early_setup+0x9c
2. Report on s390:
vsnprintf invocations, are broken on s390. For example, the early boot
output now looks like this where the first (efault) should be
the linux_banner:
[ 0.099985] (efault)
[ 0.099985] setup: Linux is running as a z/VM guest operating system in 64-bit mode
[ 0.100066] setup: The maximum memory size is 8192MB
[ 0.100070] cma: Reserved 4 MiB at (efault)
[ 0.100100] numa: NUMA mode: (efault)
The reason for this, is that the code assumes that
probe_kernel_address() works very early. This however is not true on
at least s390. Uaccess on KERNEL_DS works only after page tables have
been setup on s390, which happens with setup_arch()->paging_init().
Any probe_kernel_address() invocation before that will return -EFAULT.
Fixes: 3e5903eb9cff70730 ("vsprintf: Prevent crash when dereferencing invalid pointers")
Link: http://lkml.kernel.org/r/[email protected]
Cc: Andy Shevchenko <[email protected]>
Cc: Rasmus Villemoes <[email protected]>
Cc: "Tobin C . Harding" <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Sergey Senozhatsky <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: [email protected]
Cc: Michael Ellerman <[email protected]>
Cc: [email protected]
Cc: Russell Currey <[email protected]>
Cc: Christophe Leroy <[email protected]>
Cc: Stephen Rothwell <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: Martin Schwidefsky <[email protected]>
Cc: Petr Mladek <[email protected]>
Reviewed-by: Sergey Senozhatsky <[email protected]>
Signed-off-by: Petr Mladek <[email protected]>
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Fix sparse warning:
lib/vsprintf.c:673:6: warning:
symbol 'pointer_string' was not declared. Should it be static?
Link: http://lkml.kernel.org/r/[email protected]
To: <[email protected]>
To: <[email protected]>
To: <[email protected]>
To: <[email protected]>
Signed-off-by: YueHaibing <[email protected]>
Signed-off-by: Petr Mladek <[email protected]>
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The inlined error messages must be used carefully because
they need to fit into the given buffer.
Handle them using a custom wrapper that makes people aware
of the problem. Also define a reasonable hard limit to
avoid a completely insane usage.
Suggested-by: Sergey Senozhatsky <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
To: Rasmus Villemoes <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: "Tobin C . Harding" <[email protected]>
Cc: Joe Perches <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Sergey Senozhatsky <[email protected]>
Cc: [email protected]
Reviewed-by: Sergey Senozhatsky <[email protected]>
Reviewed-by: Andy Shevchenko <[email protected]>
Signed-off-by: Petr Mladek <[email protected]>
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We are able to detect invalid values handled by %p[iI] printk specifier.
The current error message is "invalid address". It might cause confusion
against "(efault)" reported by the generic valid_pointer_address() check.
Let's unify the style and use the more appropriate error code description
"(einval)".
Link: http://lkml.kernel.org/r/[email protected]
To: Rasmus Villemoes <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: "Tobin C . Harding" <[email protected]>
Cc: Joe Perches <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Sergey Senozhatsky <[email protected]>
Cc: [email protected]
Reviewed-by: Sergey Senozhatsky <[email protected]>
Reviewed-by: Andy Shevchenko <[email protected]>
Signed-off-by: Petr Mladek <[email protected]>
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We already prevent crash when dereferencing some obviously broken
pointers. But the handling is not consistent. Sometimes we print "(null)"
only for pure NULL pointer, sometimes for pointers in the first
page and sometimes also for pointers in the last page (error codes).
Note that printk() call this code under logbuf_lock. Any recursive
printks are redirected to the printk_safe implementation and the messages
are stored into per-CPU buffers. These buffers might be eventually flushed
in printk_safe_flush_on_panic() but it is not guaranteed.
This patch adds a check using probe_kernel_read(). It is not a full-proof
test. But it should help to see the error message in 99% situations where
the kernel would silently crash otherwise.
Also it makes the error handling unified for "%s" and the many %p*
specifiers that need to read the data from a given address. We print:
+ (null) when accessing data on pure pure NULL address
+ (efault) when accessing data on an invalid address
It does not affect the %p* specifiers that just print the given address
in some form, namely %pF, %pf, %pS, %ps, %pB, %pK, %px, and plain %p.
Note that we print (efault) from security reasons. In fact, the real
address can be seen only by %px or eventually %pK.
Link: http://lkml.kernel.org/r/[email protected]
To: Rasmus Villemoes <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: "Tobin C . Harding" <[email protected]>
Cc: Joe Perches <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Sergey Senozhatsky <[email protected]>
Cc: [email protected]
Reviewed-by: Sergey Senozhatsky <[email protected]>
Reviewed-by: Andy Shevchenko <[email protected]>
Signed-off-by: Petr Mladek <[email protected]>
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There are few printk formats that make sense only with two or more
specifiers. Also some specifiers make sense only when a kernel feature
is enabled.
The handling of unknown specifiers is inconsistent and not helpful.
Using WARN() looks like an overkill for this type of error. pr_warn()
is not good either. It would by handled via printk_safe buffer and
it might be hard to match it with the problematic string.
A reasonable compromise seems to be writing the unknown format specifier
into the original string with a question mark, for example (%pC?).
It should be self-explaining enough. Note that it is in brackets
to follow the (null) style.
Note that it introduces a warning about that test_hashed() function
is unused. It is going to be used again by a later patch.
Link: http://lkml.kernel.org/r/[email protected]
To: Rasmus Villemoes <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: "Tobin C . Harding" <[email protected]>
Cc: Joe Perches <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Sergey Senozhatsky <[email protected]>
Cc: [email protected]
Reviewed-by: Sergey Senozhatsky <[email protected]>
Reviewed-by: Andy Shevchenko <[email protected]>
Signed-off-by: Petr Mladek <[email protected]>
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Move code from the long pointer() function. We are going to improve
error handling that will make it even more complicated.
This patch does not change the existing behavior.
Link: http://lkml.kernel.org/r/[email protected]
To: Rasmus Villemoes <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: "Tobin C . Harding" <[email protected]>
Cc: Joe Perches <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Sergey Senozhatsky <[email protected]>
Cc: [email protected]
Cc: Kees Cook <[email protected]>
Reviewed-by: Sergey Senozhatsky <[email protected]>
Reviewed-by: Andy Shevchenko <[email protected]>
Signed-off-by: Petr Mladek <[email protected]>
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Move the code from the long pointer() function. We are going to improve
error handling that will make it more complicated.
This patch does not change the existing behavior.
Link: http://lkml.kernel.org/r/[email protected]
To: Rasmus Villemoes <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: "Tobin C . Harding" <[email protected]>
Cc: Joe Perches <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Sergey Senozhatsky <[email protected]>
Cc: [email protected]
Reviewed-by: Sergey Senozhatsky <[email protected]>
Reviewed-by: Andy Shevchenko <[email protected]>
Signed-off-by: Petr Mladek <[email protected]>
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Move the non-trivial code from the long pointer() function. We are going
to improve error handling that will make it even more complicated.
This patch does not change the existing behavior.
Link: http://lkml.kernel.org/r/[email protected]
To: Rasmus Villemoes <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: "Tobin C . Harding" <[email protected]>
Cc: Joe Perches <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Sergey Senozhatsky <[email protected]>
Cc: [email protected]
Reviewed-by: Sergey Senozhatsky <[email protected]>
Reviewed-by: Andy Shevchenko <[email protected]>
Signed-off-by: Petr Mladek <[email protected]>
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We are going to check the address using probe_kernel_address(). It will
be more expensive and it does not make sense for well known address.
This patch splits the string() function. The variant without the check
is then used on locations that handle string constants or strings defined
as local variables.
This patch does not change the existing behavior.
Link: http://lkml.kernel.org/r/[email protected]
To: Rasmus Villemoes <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: "Tobin C . Harding" <[email protected]>
Cc: Joe Perches <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Sergey Senozhatsky <[email protected]>
Cc: [email protected]
Reviewed-by: Andy Shevchenko <[email protected]>
Signed-off-by: Petr Mladek <[email protected]>
Reviewed-by: Sergey Senozhatsky <[email protected]>
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restricted_pointer() pretends that it prints the address when kptr_restrict
is set to zero. But it is never called in this situation. Instead,
pointer() falls back to ptr_to_id() and hashes the pointer.
This patch removes the potential confusion. klp_restrict is checked only
in restricted_pointer().
It actually fixes a small race when the address might get printed unhashed:
CPU0 CPU1
pointer()
if (!kptr_restrict)
/* for example set to 2 */
restricted_pointer()
/* echo 0 >/proc/sys/kernel/kptr_restrict */
proc_dointvec_minmax_sysadmin()
klpr_restrict = 0;
switch(kptr_restrict)
case 0:
break:
number()
Fixes: ef0010a30935de4e0211 ("vsprintf: don't use 'restricted_pointer()' when not restricting")
Link: http://lkml.kernel.org/r/[email protected]
To: Andy Shevchenko <[email protected]>
To: Rasmus Villemoes <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: "Tobin C . Harding" <[email protected]>
Cc: Joe Perches <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Sergey Senozhatsky <[email protected]>
Cc: [email protected]
Cc: Kees Cook <[email protected]>
Reviewed-by: Andy Shevchenko <[email protected]>
Reviewed-by: Steven Rostedt (VMware) <[email protected]>
Reviewed-by: Sergey Senozhatsky <[email protected]>
Signed-off-by: Petr Mladek <[email protected]>
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This is just a preparation step for further changes.
The patch does not change the code.
Link: http://lkml.kernel.org/r/[email protected]
To: Rasmus Villemoes <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: "Tobin C . Harding" <[email protected]>
Cc: Joe Perches <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Sergey Senozhatsky <[email protected]>
Cc: [email protected]
Reviewed-by: Andy Shevchenko <[email protected]>
Reviewed-by: Sergey Senozhatsky <[email protected]>
Signed-off-by: Petr Mladek <[email protected]>
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git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk
Pull printk updates from Petr Mladek:
- Allow to sort mixed lines by an extra information about the caller
- Remove no longer used LOG_PREFIX.
- Some clean up and documentation update.
* tag 'printk-for-5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk:
printk/docs: Add extra integer types to printk-formats
printk: Remove no longer used LOG_PREFIX.
lib/vsprintf: Remove %pCr remnant in comment
printk: Pass caller information to log_store().
printk: Add caller information to printk() output.
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At the time of commit d048419311ff ("lib/vsprintf.c: expand field_width
to 24 bits"), there was no compiletime_assert/BUILD_BUG/.... variant
that could be used outside function scope. Now we have static_assert(),
so move the assertion next to the definition instead of hiding it in
some arbitrary function.
Also add the appropriate #include to avoid relying on build_bug.h being
pulled in via some arbitrary chain of includes.
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Rasmus Villemoes <[email protected]>
Cc: Alexander Viro <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Luc Van Oostenryck <[email protected]>
Cc: Masahiro Yamada <[email protected]>
Cc: Nick Desaulniers <[email protected]>
Cc: Alexey Dobriyan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Support for "%pCr" was removed, but a reference in a comment was
forgotten.
Fixes: 666902e42fd8344b ("lib/vsprintf: Remove atomic-unsafe support for %pCr")
Link: http://lkml.kernel.org/r/[email protected]
To: Andy Shevchenko <[email protected]>
To: Andrew Morton <[email protected]>
Cc: [email protected]
Signed-off-by: Geert Uytterhoeven <[email protected]>
Signed-off-by: Petr Mladek <[email protected]>
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There are users which print time and date represented by content of
struct rtc_time in human readable format.
Instead of open coding that each time introduce %ptR[dt][r] specifier.
Cc: Arnd Bergmann <[email protected]>
Cc: Bartlomiej Zolnierkiewicz <[email protected]>
Cc: Dmitry Torokhov <[email protected]>
Cc: Geert Uytterhoeven <[email protected]>
Cc: Guan Xuetao <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jason Wessel <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Jonathan Hunter <[email protected]>
Cc: Krzysztof Kozlowski <[email protected]>
Cc: "Rafael J. Wysocki" <[email protected]>
Cc: Thierry Reding <[email protected]>
Cc: Petr Mladek <[email protected]>
Signed-off-by: Andy Shevchenko <[email protected]>
Reviewed-by: Petr Mladek <[email protected]>
Signed-off-by: Alexandre Belloni <[email protected]>
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git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux
Pull Devicetree updates from Rob Herring:
"A bit bigger than normal as I've been busy this cycle.
There's a few things with dependencies and a few things subsystem
maintainers didn't pick up, so I'm taking them thru my tree.
The fixes from Johan didn't get into linux-next, but they've been
waiting for some time now and they are what's left of what subsystem
maintainers didn't pick up.
Summary:
- Sync dtc with upstream version v1.4.7-14-gc86da84d30e4
- Work to get rid of direct accesses to struct device_node name and
type pointers in preparation for removing them. New helpers for
parsing DT cpu nodes and conversions to use the helpers. printk
conversions to %pOFn for printing DT node names. Most went thru
subystem trees, so this is the remainder.
- Fixes to DT child node lookups to actually be restricted to child
nodes instead of treewide.
- Refactoring of dtb targets out of arch code. This makes the support
more uniform and enables building all dtbs on c6x, microblaze, and
powerpc.
- Various DT binding updates for Renesas r8a7744 SoC
- Vendor prefixes for Facebook, OLPC
- Restructuring of some ARM binding docs moving some peripheral
bindings out of board/SoC binding files
- New "secure-chosen" binding for secure world settings on ARM
- Dual licensing of 2 DT IRQ binding headers"
* tag 'devicetree-for-4.20' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux: (78 commits)
ARM: dt: relicense two DT binding IRQ headers
power: supply: twl4030-charger: fix OF sibling-node lookup
NFC: nfcmrvl_uart: fix OF child-node lookup
net: stmmac: dwmac-sun8i: fix OF child-node lookup
net: bcmgenet: fix OF child-node lookup
drm/msm: fix OF child-node lookup
drm/mediatek: fix OF sibling-node lookup
of: Add missing exports of node name compare functions
dt-bindings: Add OLPC vendor prefix
dt-bindings: misc: bk4: Add device tree binding for Liebherr's BK4 SPI bus
dt-bindings: thermal: samsung: Add SPDX license identifier
dt-bindings: clock: samsung: Add SPDX license identifiers
dt-bindings: timer: ostm: Add R7S9210 support
dt-bindings: phy: rcar-gen2: Add r8a7744 support
dt-bindings: can: rcar_can: Add r8a7744 support
dt-bindings: timer: renesas, cmt: Document r8a7744 CMT support
dt-bindings: watchdog: renesas-wdt: Document r8a7744 support
dt-bindings: thermal: rcar: Add device tree support for r8a7744
Documentation: dt: Add binding for /secure-chosen/stdout-path
dt-bindings: arm: zte: Move sysctrl bindings to their own doc
...
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git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk
Pull printk updates from Petr Mladek:
- Fix two more locations where printf formatting leaked pointers
- Better log_buf_len parameter handling
- Add prefix to messages from printk code
- Do not miss messages on other consoles when the log is replayed on a
new one
- Reduce race between console registration and panic() when the log
might get replayed on all consoles
- Some cont buffer code clean up
- Call console only when there is something to do (log vs cont buffer)
* tag 'printk-for-4.20' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk:
lib/vsprintf: Hash printed address for netdev bits fallback
lib/vsprintf: Hash legacy clock addresses
lib/vsprintf: Prepare for more general use of ptr_to_id()
lib/vsprintf: Make ptr argument conts in ptr_to_id()
printk: fix integer overflow in setup_log_buf()
printk: do not preliminary split up cont buffer
printk: lock/unlock console only for new logbuf entries
printk: keep kernel cont support always enabled
printk: Give error on attempt to set log buffer length to over 2G
printk: Add KBUILD_MODNAME and remove a redundant print prefix
printk: Correct wrong casting
printk: Fix panic caused by passing log_buf_len to command line
printk: CON_PRINTBUFFER console registration is a bit racy
printk: Do not miss new messages when replaying the log
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Pull documentation updates from Jonathan Corbet:
"This is a fairly typical cycle for documentation. There's some welcome
readability improvements for the formatted output, some LICENSES
updates including the addition of the ISC license, the removal of the
unloved and unmaintained 00-INDEX files, the deprecated APIs document
from Kees, more MM docs from Mike Rapoport, and the usual pile of typo
fixes and corrections"
* tag 'docs-4.20' of git://git.lwn.net/linux: (41 commits)
docs: Fix typos in histogram.rst
docs: Introduce deprecated APIs list
kernel-doc: fix declaration type determination
doc: fix a typo in adding-syscalls.rst
docs/admin-guide: memory-hotplug: remove table of contents
doc: printk-formats: Remove bogus kobject references for device nodes
Documentation: preempt-locking: Use better example
dm flakey: Document "error_writes" feature
docs/completion.txt: Fix a couple of punctuation nits
LICENSES: Add ISC license text
LICENSES: Add note to CDDL-1.0 license that it should not be used
docs/core-api: memory-hotplug: add some details about locking internals
docs/core-api: rename memory-hotplug-notifier to memory-hotplug
docs: improve readability for people with poorer eyesight
yama: clarify ptrace_scope=2 in Yama documentation
docs/vm: split memory hotplug notifier description to Documentation/core-api
docs: move memory hotplug description into admin-guide/mm
doc: Fix acronym "FEKEK" in ecryptfs
docs: fix some broken documentation references
iommu: Fix passthrough option documentation
...
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When converting from text to rst, the kobjects section and its sole
subsection about device tree nodes were coalesced into a single section,
yielding an inconsistent result.
Remove all references to kobjects, as
1. Device tree object pointers are not compatible to kobject pointers
(the former may embed the latter, though), and
2. there are no printk formats defined for kobject types.
Update the vsprintf() source code comments to match the above.
Fixes: b3ed23213eab1e08 ("doc: convert printk-formats.txt to rst")
Signed-off-by: Geert Uytterhoeven <[email protected]>
Signed-off-by: Jonathan Corbet <[email protected]>
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The handler for "%pN" falls back to printing the raw pointer value when
using a different format than the (sole supported) special format
"%pNF", potentially leaking sensitive information regarding the kernel
layout in memory.
Avoid this leak by printing the hashed address instead.
Note that there are no in-tree users of the fallback.
Fixes: ad67b74d2469d9b8 ("printk: hash addresses printed with %p")
Link: http://lkml.kernel.org/r/[email protected]
To: "Tobin C . Harding" <[email protected]>
To: Andrew Morton <[email protected]>
To: Jonathan Corbet <[email protected]>
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Geert Uytterhoeven <[email protected]>
Reviewed-by: Andy Shevchenko <[email protected]>
Signed-off-by: Petr Mladek <[email protected]>
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On platforms using the Common Clock Framework, "%pC" prints the clock's
name. On legacy platforms, it prints the unhashed clock's address,
potentially leaking sensitive information regarding the kernel layout in
memory.
Avoid this leak by printing the hashed address instead. To distinguish
between clocks, a 32-bit unique identifier is as good as an actual
pointer value.
Fixes: ad67b74d2469d9b8 ("printk: hash addresses printed with %p")
Link: http://lkml.kernel.org/r/[email protected]
To: "Tobin C . Harding" <[email protected]>
To: Andrew Morton <[email protected]>
To: Jonathan Corbet <[email protected]>
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Geert Uytterhoeven <[email protected]>
Reviewed-by: Andy Shevchenko <[email protected]>
Signed-off-by: Petr Mladek <[email protected]>
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Move the function and its dependencies up so it can be called from
special pointer type formatting routines.
Link: http://lkml.kernel.org/r/[email protected]
To: "Tobin C . Harding" <[email protected]>
To: Andrew Morton <[email protected]>
To: Jonathan Corbet <[email protected]>
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Geert Uytterhoeven <[email protected]>
Reviewed-by: Andy Shevchenko <[email protected]>
[[email protected]: Split into separate patch]
Signed-off-by: Petr Mladek <[email protected]>
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Make the ptr argument const to avoid adding casts in future callers.
Link: http://lkml.kernel.org/r/[email protected]
To: "Tobin C . Harding" <[email protected]>
To: Andrew Morton <[email protected]>
To: Jonathan Corbet <[email protected]>
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Geert Uytterhoeven <[email protected]>
Reviewed-by: Andy Shevchenko <[email protected]>
[[email protected]: split into separate patch]
Signed-off-by: Petr Mladek <[email protected]>
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The functions vbin_printf() and bstr_printf() are used by trace_printk() to
try to keep the overhead down during printing. trace_printk() uses
vbin_printf() at the time of execution, as it only scans the fmt string to
record the printf values into the buffer, and then uses vbin_printf() to do
the conversions to print the string based on the format and the saved
values in the buffer.
This is an issue for dereferenced pointers, as before commit 841a915d20c7b,
the processing of the pointer could happen some time after the pointer value
was recorded (reading the trace buffer). This means the processing of the
value at a later time could show different results, or even crash the
system, if the pointer no longer existed.
Commit 841a915d20c7b addressed this by processing dereferenced pointers at
the time of execution and save the result in the ring buffer as a string.
The bstr_printf() would then treat these pointers as normal strings, and
print the value. But there was an off-by-one bug here, where after
processing the argument, it move the pointer only "strlen(arg)" which made
the arg pointer not point to the next argument in the ring buffer, but
instead point to the nul character of the last argument. This causes any
values after a dereferenced pointer to be corrupted.
Cc: [email protected]
Fixes: 841a915d20c7b ("vsprintf: Do not have bprintf dereference pointers")
Reported-by: Nikolay Borisov <[email protected]>
Tested-by: Nikolay Borisov <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
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In preparation to remove the node name pointer from struct device_node,
convert the node name print to get the node name from the full name.
Reviewed-by: Frank Rowand <[email protected]>
Signed-off-by: Rob Herring <[email protected]>
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git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random
Pull random updates from Ted Ts'o:
"Some changes to trust cpu-based hwrng (such as RDRAND) for
initializing hashed pointers and (optionally, controlled by a config
option) to initialize the CRNG to avoid boot hangs"
* tag 'random_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random:
random: Make crng state queryable
random: remove preempt disabled region
random: add a config option to trust the CPU's hwrng
vsprintf: Add command line option debug_boot_weak_hash
vsprintf: Use hw RNG for ptr_key
random: Return nbytes filled from hw RNG
random: Fix whitespace pre random-bytes work
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This patch avoids that gcc reports the following when building with W=1:
lib/vsprintf.c:1941:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
switch (fmt[1]) {
^~~~~~
Fixes: 7b1924a1d930eb2 ("vsprintf: add printk specifier %px")
Link: http://lkml.kernel.org/r/[email protected]
Cc: [email protected]
Cc: Bart Van Assche <[email protected]>
Cc: Pantelis Antoniou <[email protected]>
Cc: Joe Perches <[email protected]>
Cc: Rob Herring <[email protected]>
Cc: v4.15+ <[email protected]>
Signed-off-by: Bart Van Assche <[email protected]>
Signed-off-by: Petr Mladek <[email protected]>
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Currently printing [hashed] pointers requires enough entropy to be
available. Early in the boot sequence this may not be the case
resulting in a dummy string '(____ptrval____)' being printed. This
makes debugging the early boot sequence difficult. We can relax the
requirement to use cryptographically secure hashing during debugging.
This enables debugging while keeping development/production kernel
behaviour the same.
If new command line option debug_boot_weak_hash is enabled use
cryptographically insecure hashing and hash pointer value immediately.
Reviewed-by: Steven Rostedt (VMware) <[email protected]>
Signed-off-by: Tobin C. Harding <[email protected]>
Signed-off-by: Theodore Ts'o <[email protected]>
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Currently we must wait for enough entropy to become available before
hashed pointers can be printed. We can remove this wait by using the
hw RNG if available.
Use hw RNG to get keying material.
Reviewed-by: Steven Rostedt (VMware) <[email protected]>
Suggested-by: Kees Cook <[email protected]>
Signed-off-by: Tobin C. Harding <[email protected]>
Signed-off-by: Theodore Ts'o <[email protected]>
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git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk
Pull printk updates from Petr Mladek:
- Help userspace log daemons to catch up with a flood of messages. They
will get woken after each message even if the console is far behind
and handled by another process.
- Flush printk safe buffers safely even when panic() happens in the
normal context.
- Fix possible va_list reuse when race happened in printk_safe().
- Remove %pCr printf format to prevent sleeping in the atomic context.
- Misc vsprintf code cleanup.
* tag 'printk-for-4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk:
printk: drop in_nmi check from printk_safe_flush_on_panic()
lib/vsprintf: Remove atomic-unsafe support for %pCr
serial: sh-sci: Stop using printk format %pCr
thermal: bcm2835: Stop using printk format %pCr
clk: renesas: cpg-mssr: Stop using printk format %pCr
printk: fix possible reuse of va_list variable
printk: wake up klogd in vprintk_emit
vsprintf: Tweak pF/pf comment
lib/vsprintf: Mark expected switch fall-through
lib/vsprintf: Replace space with '_' before crng is ready
lib/vsprintf: Deduplicate pointer_string()
lib/vsprintf: Move pointer_string() upper
lib/vsprintf: Make flag_spec global
lib/vsprintf: Make strspec global
lib/vsprintf: Make dec_spec global
lib/test_printf: Mark big constant with UL
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"%pCr" formats the current rate of a clock, and calls clk_get_rate().
The latter obtains a mutex, hence it must not be called from atomic
context.
Remove support for this rarely-used format, as vsprintf() (and e.g.
printk()) must be callable from any context.
Any remaining out-of-tree users will start seeing the clock's name
printed instead of its rate.
Reported-by: Jia-Ju Bai <[email protected]>
Fixes: 900cca2944254edd ("lib/vsprintf: add %pC{,n,r} format specifiers for clocks")
Link: http://lkml.kernel.org/r/[email protected]
To: Jia-Ju Bai <[email protected]>
To: Jonathan Corbet <[email protected]>
To: Michael Turquette <[email protected]>
To: Stephen Boyd <[email protected]>
To: Zhang Rui <[email protected]>
To: Eduardo Valentin <[email protected]>
To: Eric Anholt <[email protected]>
To: Stefan Wahren <[email protected]>
To: Greg Kroah-Hartman <[email protected]>
Cc: Sergey Senozhatsky <[email protected]>
Cc: Petr Mladek <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: Geert Uytterhoeven <[email protected]>
Cc: [email protected] # 4.1+
Signed-off-by: Geert Uytterhoeven <[email protected]>
Signed-off-by: Petr Mladek <[email protected]>
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Reviewing Tobin's patches for getting pointers out early before
entropy has been established, I noticed that there's a lone smp_mb() in
the code. As with most lone memory barriers, this one appears to be
incorrectly used.
We currently basically have this:
get_random_bytes(&ptr_key, sizeof(ptr_key));
/*
* have_filled_random_ptr_key==true is dependent on get_random_bytes().
* ptr_to_id() needs to see have_filled_random_ptr_key==true
* after get_random_bytes() returns.
*/
smp_mb();
WRITE_ONCE(have_filled_random_ptr_key, true);
And later we have:
if (unlikely(!have_filled_random_ptr_key))
return string(buf, end, "(ptrval)", spec);
/* Missing memory barrier here. */
hashval = (unsigned long)siphash_1u64((u64)ptr, &ptr_key);
As the CPU can perform speculative loads, we could have a situation
with the following:
CPU0 CPU1
---- ----
load ptr_key = 0
store ptr_key = random
smp_mb()
store have_filled_random_ptr_key
load have_filled_random_ptr_key = true
BAD BAD BAD! (you're so bad!)
Because nothing prevents CPU1 from loading ptr_key before loading
have_filled_random_ptr_key.
But this race is very unlikely, but we can't keep an incorrect smp_mb() in
place. Instead, replace the have_filled_random_ptr_key with a static_branch
not_filled_random_ptr_key, that is initialized to true and changed to false
when we get enough entropy. If the update happens in early boot, the
static_key is updated immediately, otherwise it will have to wait till
entropy is filled and this happens in an interrupt handler which can't
enable a static_key, as that requires a preemptible context. In that case, a
work_queue is used to enable it, as entropy already took too long to
establish in the first place waiting a little more shouldn't hurt anything.
The benefit of using the static key is that the unlikely branch in
vsprintf() now becomes a nop.
Link: http://lkml.kernel.org/r/[email protected]
Cc: [email protected]
Fixes: ad67b74d2469d ("printk: hash addresses printed with %p")
Acked-by: Linus Torvalds <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
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Reflect changes that have happened to pf/pF (deprecation)
specifiers in pointer() comment section.
Link: http://lkml.kernel.org/r/[email protected]
Cc: Steven Rostedt <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Joe Perches <[email protected]>
Cc: [email protected]
Signed-off-by: Sergey Senozhatsky <[email protected]>
Signed-off-by: Petr Mladek <[email protected]>
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seq_put_decimal_ull_w(m, str, val, width) prints a decimal number with a
specified minimal field width.
It is equivalent of seq_printf(m, "%s%*d", str, width, val), but it
works much faster.
== test_smaps.py
num = 0
with open("/proc/1/smaps") as f:
for x in xrange(10000):
data = f.read()
f.seek(0, 0)
==
== Before patch ==
$ time python test_smaps.py
real 0m4.593s
user 0m0.398s
sys 0m4.158s
== After patch ==
$ time python test_smaps.py
real 0m3.828s
user 0m0.413s
sys 0m3.408s
$ perf -g record python test_smaps.py
== Before patch ==
- 79.01% 3.36% python [kernel.kallsyms] [k] show_smap.isra.33
- 75.65% show_smap.isra.33
+ 48.85% seq_printf
+ 15.75% __walk_page_range
+ 9.70% show_map_vma.isra.23
0.61% seq_puts
== After patch ==
- 75.51% 4.62% python [kernel.kallsyms] [k] show_smap.isra.33
- 70.88% show_smap.isra.33
+ 24.82% seq_put_decimal_ull_w
+ 19.78% __walk_page_range
+ 12.74% seq_printf
+ 11.08% show_map_vma.isra.23
+ 1.68% seq_puts
[[email protected]: fix drivers/of/unittest.c build]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Andrei Vagin <[email protected]>
Cc: Alexey Dobriyan <[email protected]>
Cc: KAMEZAWA Hiroyuki <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.
Link: http://lkml.kernel.org/r/[email protected]
To: "Tobin C . Harding" <[email protected]>
To: [email protected]
To: Joe Perches <[email protected]>
To: [email protected]
To: Andrew Morton <[email protected]>
Signed-off-by: Andy Shevchenko <[email protected]>
Signed-off-by: Petr Mladek <[email protected]>
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Before crng is ready, output of "%p" composes of "(ptrval)" and
left padding spaces for alignment as no random address can be
generated. This seems a little strange when default string width
is larger than strlen("(ptrval)").
For example, when irq domain names are built with "%p", the nodes
under /sys/kernel/debug/irq/domains like this on AArch64 system,
[root@y irq]# ls domains/
default irqchip@ (ptrval)-2
irqchip@ (ptrval)-4 \_SB_.TCS0.QIC1 \_SB_.TCS0.QIC3
irqchip@ (ptrval) irqchip@ (ptrval)-3
\_SB_.TCS0.QIC0 \_SB_.TCS0.QIC2
The name "irqchip@ (ptrval)-2" is not so readable in console
output.
This patch replaces space with readable "_" when output needs padding.
Following is the output after applying the patch,
[root@y domains]# ls
default irqchip@(____ptrval____)-2
irqchip@(____ptrval____)-4 \_SB_.TCS0.QIC1 \_SB_.TCS0.QIC3
irqchip@(____ptrval____) irqchip@(____ptrval____)-3 \_SB_.TCS0.QIC0
\_SB_.TCS0.QIC2
There is same problem in some subsystem's dmesg output. Moreover,
someone may call "%p" in a similar case. In addition, the timing of
crng initialization done may vary on different system. So, the change
is made in vsprintf.c.
Suggested-by: Rasmus Villemoes <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
To: "Tobin C . Harding" <[email protected]>
To: [email protected]
To: Joe Perches <[email protected]>
To: [email protected]
To: Andrew Morton <[email protected]>
Cc: Joey Zheng <[email protected]>
Signed-off-by: Shunyong Yang <[email protected]>
Signed-off-by: Andy Shevchenko <[email protected]>
Signed-off-by: Petr Mladek <[email protected]>
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There is an exact code at the end of ptr_to_id().
Replace it by calling pointer_string() directly.
This is followup to the commit ad67b74d2469 ("printk: hash addresses
printed with %p").
Cc: Tobin C. Harding <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
To: "Tobin C . Harding" <[email protected]>
To: [email protected]
To: Joe Perches <[email protected]>
To: [email protected]
To: Andrew Morton <[email protected]>
Signed-off-by: Andy Shevchenko <[email protected]>
Signed-off-by: Petr Mladek <[email protected]>
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As preparatory patch to further clean up.
No functional change.
Link: http://lkml.kernel.org/r/[email protected]
To: "Tobin C . Harding" <[email protected]>
To: [email protected]
To: Joe Perches <[email protected]>
To: [email protected]
To: Andrew Morton <[email protected]>
Signed-off-by: Andy Shevchenko <[email protected]>
Signed-off-by: Petr Mladek <[email protected]>
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There are places where default specification to print flags as number
is in use.
Make it global and convert existing users.
Link: http://lkml.kernel.org/r/[email protected]
To: "Tobin C . Harding" <[email protected]>
To: [email protected]
To: Joe Perches <[email protected]>
To: [email protected]
To: Andrew Morton <[email protected]>
Signed-off-by: Andy Shevchenko <[email protected]>
Signed-off-by: Petr Mladek <[email protected]>
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There are places where default specification to print strings
is in use.
Make it global and convert existing users.
Link: http://lkml.kernel.org/r/[email protected]
To: "Tobin C . Harding" <[email protected]>
To: [email protected]
To: Joe Perches <[email protected]>
To: [email protected]
To: Andrew Morton <[email protected]>
Signed-off-by: Andy Shevchenko <[email protected]>
Signed-off-by: Petr Mladek <[email protected]>
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There are places where default specification to print decimal numbers
is in use.
Make it global and convert existing users.
Link: http://lkml.kernel.org/r/[email protected]
To: "Tobin C . Harding" <[email protected]>
To: [email protected]
To: Joe Perches <[email protected]>
To: [email protected]
To: Andrew Morton <[email protected]>
Signed-off-by: Andy Shevchenko <[email protected]>
Signed-off-by: Petr Mladek <[email protected]>
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Commit 841a915d20c7b2 ("printf: Do not have bprintf dereference pointers")
would preprocess various pointers that are dereferenced in the bprintf()
because the recording and printing are done at two different times. Some
pointers stayed dereferenced in the ring buffer because user space could
handle them (namely "%pS" and friends). Pointers that are not dereferenced
should not be processed immediately but instead just saved directly.
Cc: [email protected]
Fixes: 841a915d20c7b2 ("printf: Do not have bprintf dereference pointers")
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
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Like %pK already does, print "00000000" instead.
This confused people -- the convention is that "(null)" means you tried to
dereference a null pointer as opposed to printing the address.
Link: http://lkml.kernel.org/r/[email protected]
To: Sergey Senozhatsky <[email protected]>
To: Steven Rostedt <[email protected]>
To: [email protected]
Cc: Andrew Morton <[email protected]>
Cc: Joe Perches <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: "Roberts, William C" <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: David Laight <[email protected]>
Cc: Randy Dunlap <[email protected]>
Cc: Geert Uytterhoeven <[email protected]>
Signed-off-by: Adam Borowski <[email protected]>
Signed-off-by: Petr Mladek <[email protected]>
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